Multidimensional array into string in PHP

Question

I have a result set from a DB that returns the following array.... how do I implode this into a comma delimited string?

Array
(
 [0] => Array
 (
 [user_id] => 2
 )
 [1] => Array
 (
 [user_id] => 5
 )
 [2] => Array
 (
 [user_id] => 11
 )
)

Answer 1

$t = array_map(function (array $a) { return $a["user_id"]; }, $original_array);
$result = implode(",", $t);

(PHP 5.3+, the closure must be turned into a regular function for earlier versions)

• Vladislav Rastrusny: Don't think there is a need to confuse beginner PHP programmers with constructions of such complexity.
• Artefacto: @Fra Seriously? This is "complex"?
• Vladislav Rastrusny: Yes. Closures is not something beginners can understand very well.
• Artefacto: @Fra I don't see why. Scheme is often taught in introductory programming courses. Do you think the beginner PHP programmer cannot understand something a freshman CS undergraduate can?
• Vladislav Rastrusny: Do you see the level of the question asked? The guy doesn't know how to restructure a given array. Forget Scheme. ;)

Answer 2

$resultArray = array();
foreach($myNestedArray as $item) {
 $resultArray[]=$item['user_id'];
}
$resultString = implode(',', $resultArray);

Works on all recent PHP versions.